Abstract: Solar spectral irradiance is an important upper boundary condition in the study of the Earth's radiation budget. It is widely used in climate models, where it is directly related to the accuracy of atmospheric corrections. This paper focuses on the design of the optical structure, the radiometric calibration method, the measured solar reference spectrum and the measurement consistency. The satellite-borne spectroradiometer can be divided into grating type and prism type. The dispersion of grating type is much more uniform, such as ESA SOLSPEC. It consists three double grating monochromators, which can be used to observe different bands and synthesize to a spectrum covering 200 nm to 2500 nm. For the prism type, NASA SIM uses a Féry prism which can also cover a spectrum scanning from 200 nm to 2500 nm, with a nonlinear dispersion. The satellite-borne spectrometer needs to be calibrated before launch. The radiometric calibration can be traceable to high-temperature blackbody and cryogenic radiometer. Since the blackbody and the sun are both non polarized, it is much easier to use the blackbody. Since the uncertainty of blackbody radiation is related to the temperature uncertainty, the advancement of high-temperature fixed point blackbody technology can bring a lower measurement uncertainty. Comparing to blackbody, using tunable laser and tracing back to cryogenic radiometer can provide a much higher calibration accuracy, and it has already been applied to SIM, CSIM and other solar spectroradiometers. The solar spectrum comparison shows that, the disagreement is much larger in the ultraviolet comparing to the visible and infrared, and the disagreements exceed the respective claimed measurement uncertainties, especially at the wavelengths above 1300 nm. For the solar spectral irradiance measurement in China, it is necessary to further improve laboratory calibration techniques to achieve a lower measurement uncertainty. At the same time, we need to improve the development capability of satellite-borne spectroradiometer and ensure high onboard calibration accuracy to provide a better long-term stability, finally improving the measurement accuracy of the solar spectral irradiance.